1. Field of the Invention
The present invention relates to an aqueous, foamable composition useful for formation fracturing including an ionically coupled gel system, where the compositions are well suited in fracturing formation where there are insufficient or non-existent hydration units. The present invention also includes methods for making and using the compositions to fracture formation with insufficient hydration units.
More particularly, the present invention relates to an aqueous, foamable composition useful for formation fracturing including: water, an ionically coupled gel system including an anionic or cationic polymer and an oppositely charged foaming agent and a gas, where the gel system and the gas are present in amount sufficient to form an ionically coupled, foamed fracturing composition. The compositions are well suited in fracturing formation where there are insufficient or non-existent hydration units. The present invention also includes methods for making and using the compositions to fracture formation with insufficient hydration units.
2. Description of the Related Art
Historically the use of gelled fracturing fluids in locations where there is no existence of hydration units has been solved by hydrating a lineal gel at different locations. After hydrating the linear gel, transporting the hydrated linear gel to the fracturing location. A more recent approach has been addressed by using a viscoelastic system (VES), where the gel systems are generated from worm-like micellar structures made from a surfactant system such as cetyl t-butyl ammonium chloride, which builds up viscosity immediately when it gets in contact with a brine system.
In the past, it combination of either anionic surfactants, cationic surfactants, no-ionic surfactants and amphoteric surfactants have been used to create a gel system for fracturing applications. Only in U.S. Pat. No. 7,205,262 is there even a mention of using gels including oppositely charged components for fracturing applications, but the patent did not mention using such systems in foamed fracturing applications.
In U.S. Pat. No. 5,169,441 suggested the use of Zeta Potential for characterizing particulates such as pigments treated with cationic polymers. U.S. Pat. No. 5,846,308 disclosed the stabilization of a rosin dispersion for use as a sizing composition by treating it with a “cationic colloidal coacervate” which may include both a cationic polymer and an anionic surfactant; the finished sizing composition is to have a Zeta Potential of at least 20 millivolts. Poly(diallyldimethyl ammonium chloride), sometimes known as polyDADMAC, is the preferred cationic polymer. Also, U.S. Pat. No. 6,315,824 describes a similar coacervate stabilizing system used for hydrophobic non-rosin sizing agents, which may be liquid as well as solid. See also U.S. Pat. No. 4,507,210, which suggests a correlation of Zeta Potential to certain filtration properties in the treatment of shale and clay in hydrocarbon recovery; see also U.S. Pat. No. 5,196,401.
Other compositions comprising a cationic polymer and an anionic surfactant, often in high ratios of anionic surfactant to cationic polymer, may be found in U.S. Pat. No. 6,110,451, U.S. Pat. No. 4,948,576, and the shampoo and other personal care products described by U.S. Pat. Nos. 6,297,203, 6,221,817, U.S. Pat. No. 6,284,230, (which also describes betaines) U.S. Pat. No. 5,137,715, and U.S. Pat. No. 6,248,317.
In the field of hydrocarbon recovery from the earth, formation fracturing fluids proposed in CA2,257,699 combine anionic surfactants such as sodium xylene sulfonate and cationic surfactants such as N,N,N, trimethyl-1-octadecammonium chloride to make a gel said to be viscoelastic. Carbon dioxide is added to similar combinations in CA2,257,697 to generate a foam. U.S. Pat. No. 4,409,110, describe formation flooding compositions which may comprise cationic polymers and anionic surfactants. Numerous combinations of surfactants and other compounds are proposed in U.S. Pat. No. 6,258,859 (WO 98/56497; PCT/US/12067). See also the compositions said to be viscoelastic and proposed for well treatment in U.S. Pat. No. 6,232,274 and U.S. Pat. No. 6,194,356.
Combinations of cationic polymers, betaines, and anionic surfactants may be inferred from the numerous combinations of materials that are possibly viscoelastic within the disclosure in U.S. Pat. No. 5,956,502, dealing with compositions for use on the hair and skin. See also the combination of cationic polymer with anionic surfactants for use as an automatic dishwashing detergent, in U.S. Pat. No. 6,281,180.
In U.S. Pat. Nos. 7,182,239 and 7,205,262, disclosed a micellar combinations of cationic or anionic polymers and oppositely charged surfactants are made preferably with C6 to C23 alcohols in proportions coordinated in aqueous media with the aid of Zeta Potential measurements. The resulting gels are useful in drilling and formation fracturing in hydrocarbon recovery, manifesting excellent proppant suspending properties in low concentrations of polymer and surfactant as compared to the prior art.
Although there are foaming systems of use in fracturing formations that do not have adequate hydration units, there is still a need in the art for other fracturing compositions that can be used to fracture formation including formation having inadequate or no hydration units.